Objective:
Demonstrate that using low permeability tarps (e.g., TIF) can improve efficacy while controlling emissions and can be potentially used with lower rates.

Approach:
Two field trials will be conducted to collect soil fumigant (1,3-D, chloropicrin and methyl iodide) and pest control (nematode, pathogen, and weed) data under TIF tarps. Fields with naturally occurring nematode and pathogen populations will be selected. Treatments (4 replicates) will include: control (no fumigation), full rate (maximum allowed) in bare soil, under standard tarp, and TIF tarp, and reduced rates (2/3 and 1/2 of full rate) under TIF. Soil-gas concentrations will be monitored at pest sampling locations and depths. Correlation between fumigant dosage and pest control, and treatment effects will be statistically analyzed. Tarp permeability will be measured before and after installation. Fumigant change in the air under tarp will be monitored to estimate the proper time for the safe removal of TIF tarps to minimize exposure risks, a major concern of regulatory agencies. Almond trees will be planted the following spring and tree responses to treatments will be monitored.